18 THE SEA-SHORE 



with such force that the surrounding water cannot 

 give way fast enough before them. So they push 

 the cuttle backwards so swiftly that if it were 

 to dart across the pool you would hardly be able 

 to follow its movements. 



The third use of the siphon tubes is a very 

 strange one indeed. Sometimes while you are 

 looking at a cuttle in a rock-pool, the water all 

 round it will suddenly become quite dark, just as 

 if a quantity of ink had been poured into the pool. 

 Aid so it has; for inside its body the cuttle has 

 a bag which contains a quantity of a deep black 

 liquid called "sepia." This bag is surrounded 

 by powerful muscles, and opens into the siphon 

 tubes; so that when the animal contracts the 

 muscles, the sepia is squirted out into the pool. 

 It always does this if it is frightened ; and under 

 cover of the darkened water it nearly always suc- 

 ceeds in making its escape. 



Inside its body the cuttle also has a very curious 

 object which is generally called a "cuttle-bone." 

 It is not really a bone, however, but is made of 

 almost pure chalk, and seems to act as a kind of 

 support for the bodily organs. 



Another very odd thing about the cuttle is the 

 way in which it lays its eggs. These look just 

 like purple grapes, and each has a small stalk, by 

 means of which they are fastened together in 

 bunches. Indeed, the fishermen always call them 

 " sea-grapes." You may often find them lying about 



